How do you spot a future world leader?

A US scheme to pinpoint future VIPs has spent 70 years introducing power-brokers-to-be to the American way. So how can you tell who will one day be a head of state?

They're out there, somewhere, embarking on their relentless climb to the top.

The next generation of politicians, cultural pioneers, business executives and media voices are starting their first jobs, desperate to escape obscurity, determined to make a name for themselves.

All you have to do is find them.

Predicting who will one day run our lives might not be an easy task, but a little-known scheme run by the US State Department has demonstrated an uncanny capacity to pinpoint these leaders-in-waiting.

It has received little attention during its history, but since 1940 the International Visitor Leader Program (IVLP) has proved remarkably prescient when it comes to guessing who might one day govern the planet.

A history of talent-spotting

1940 - US begins cultural exchanges for the first time under the guidance of Nelson Rockefeller

1948: Smith-Mundt Act creates agency to "promote a better understanding of the United States in other countries, and to increase mutual understanding"

1950: Foreign Leader Program established, later renamed International Visitor Program

2004: name changed to International Visitor Leadership Program

As part of the highly prestigious - and expensive - programme, participants are hand-picked to spend typically three weeks visiting Washington DC and three additional towns or cities, meeting their counterparts and other VIPs and experts - all highly valuable networking experience for any ambitious young man or woman on the climb.

Of the current cabinet, some 11 members are alumni of the scheme, according to the US Embassy in London.

Former prime ministers Tony Blair, Gordon Brown, Margaret Thatcher and Edward Heath were all participants early in their careers.

Nor are British heads of government the only ones to have been talent-spotted. French President Nicolas Sarkozy, his Afghan counterpart Hamid Karzai, Australian Prime Minister Julia Gillard and Zimbabwean premier Morgan Tsvangirai are among serving leaders who have passed through the project's ranks.

In the UK alone, over 2,500 citizens have travelled to the US as part of the IVLP. But for those hoping to apply for this once-in-a-lifetime opportunity, admission is strictly invitation-only.

Conspiracy theorists warn the scheme is all about an imperial power meddling in the affairs of sovereign regimes, seducing their future political leaders and moulding them into Washington-approved candidates.

The IVLP and me

Muddassar Ahmed, 28, chief executive of PR agency Unitas, has visited the US twice under the scheme and formed the John Adams Society for IVLP alumni

"I was recommended by the US cultural attache in London who had seen some documentaries I had made. He was interested in my community activism.

"I wouldn't say I was hostile to the US beforehand but I did have assumptions which were challenged by seeing it for myself. I met some people I'll keep in touch with for the rest of my life.

"It was a fascinating experience. I was particularly lucky to get to meet Secretary of State Hillary Clinton's senior adviser on Muslim engagement.

"My colleagues joke that they've implanted me with an American bug.

"But I think what the experience has given me is a more considered opinion of the US."

But its supporters say it operates more subtly than that, aiming not to convert opponents but to give future opinion-formers an understanding of how America works.

One recent attendee is Victoria Eastwood, who was working as a producer on Channel 4 News when one of her State Department contacts with whom she would arrange US government interviewees for Jon Snow nominated her for the scheme.

In 2009 she was taken to New York, Nebraska, and San Francisco, where she was introduced to former US Secretary of State Condoleezza Rice.

The visit did not alter the journalist's scepticism about the 2003 invasion of Iraq, with which Ms Rice was closely associated. But she acknowledges that the experience deepened her appreciation of how the American system operates and, in turn, ensured her coverage of US affairs could offer an insider's perspective.

"I was quite conscious that I didn't want to go on some kind of propaganda trip," Victoria says.

"But what they are doing is exposing you to people in power so that if I'm looking at something like Iran sanctions I know the person who's responsible for putting that policy into practice."

Like Victoria, not all participants are aspiring politicians. The novelist Hanif Kureishi took part in 1986, four years before the Buddha of Suburbia brought him widespread public attention, and the British artist Angela Palmer is another recent recipient. Nor do all alumni go onto achieve fame and recognition.

There is, however, an obvious chicken-and-egg question - does the status of individuals singled out as future leaders become a self-fulfilling prophecy?

Prof Giles Scott-Smith, an international relations expert at Roosevelt Academy in the Netherlands, has studied the programme extensively. He acknowledges that being invited onto it carries a high degree of prestige and can bring participants into elite networks earlier in their careers than might have been the case otherwise.

But he argues that there tends to be a clear logic behind invitations, citing the example of former Dutch prime minister Jan Peter Balkenende, who was talent-spotted for the scheme by the US embassy in 1985 when he was an obscure figure, working for a city council and as a researcher for the Christian Democrat party.

They really keep track of what's going on in the House of Commons very closelyProf Giles Scott-Smith, International relations expert at Roosevelt Academy

Despite this apparently humble status, Prof Scott-Smith says Balkenende was already a keen networker, leading US officials to conclude he would be getting ahead under his own steam regardless of their intervention.

Similarly, when Nicolas Sarkozy met the mayor of New York, Ed Koch, as part of the programme while himself mayor of the Paris suburb Neuilly-sur-Seine, the future French president milked the occasion for all the publicity it was worth, Prof Scott-Smith adds - suggesting that a true potential leader will manage to get at least as much out of the visit as the State Department.

He says the programme succeeds because it comes with no strings attached, which overcomes many sceptical invitees and allows them also to feel immune from accusations of manipulation.

But he believes it is nonetheless a prime example of US "soft power" in action, shaping first impressions and casting America within the context of one's own ambitions, aspirations, ideas, and possibilities.

In the London embassy, he observes, staff do not so much conduct their own surveillance as tap into existing local knowledge about potential rising stars.

"They really keep track of what's going on in the House of Commons very closely," Prof Scott Smith says. "They'll have one political officer who is assigned to follow each political party.

What to look for in a potential leader

Prof Jonathan Gosling, director of the Centre of Leadership Studies at the University of Exeter

"It may be their personality, it might be their ambition, it might be their staying power, it might be what they've achieved already.

"Leadership is about a comfort in taking authority for themselves and for others.

"It's about having a dependable stance that others feel they can rely on.

"But sometimes, as with Winston Churchill, it's a case of cometh the hour, cometh the man - it's not something you can forsee."

"What they want to do is pick up as much local knowledge as possible. That means talking to political party leaders but it also involves having good contacts with museum directors and so on.

"It's not just a US operation. It's about mutual interest. There's this ongoing fascination with the US. We're still in a world where we look to the US for leadership, for influence, for potential sources of solutions."

Not everyone views the programme so benignly, however. Intelligence expert Robin Ramsay, editor of Lobster magazine, accepts it is likely that all the beneficiaries of the project's largesse would have risen to the top anyway.

But he argues that the notion of a major power courting the future elite of another nation state offers cause for alarm.

"I'm concerned because I think Britain should be independent," he says. "I think the idea of a foreign country interfering in our politics is worrying."

Certainly, a 2006 study by Prof Scott-Smith (PDF) suggests the programme was used in the early 1980s to reach out to young Labour politicians, including Blair and Brown, at a time when scepticism about the Atlantic alliance was prevalent within the party.

However, Philip Breeden, press counsellor at the US embassy in London, insists such concerns are misplaced. He says the scheme works to the advantage of both his country and those of the programme's alumni.

"There's an obvious benefit to have people in public life understanding each other better across national boundaries," he says. "This is people-to-people diplomacy, not country-to-country diplomacy.

"What we're looking for is people who are making a contribution to their community, who we think will advance in their chosen career path, who will serve as a good link between our two countries."

Whatever your view of the scheme, one truth remains unquestionable: our future elite are still out there. And if anyone can find them, the Americans know how to do it.